UN Women is the snappier title of The United Nations Entity for Gender Equality and the Empowerment of Women.

Watson said in the statement: "Being asked to serve as UN Women's Goodwill Ambassador is truly humbling. The chance to make a real difference is not an opportunity that everyone is given and is one I have no intention of taking lightly.

"Women's rights are something so inextricably linked with who I am, so deeply personal and rooted in my life that I can't imagine an opportunity more exciting," she continued. "I still have so much to learn, but as I progress I hope to bring more of my individual knowledge, experience and awareness to this role."

Last month Watson completed her degree in English literature at Brown University in the US.

Phumzile Mlambo-Ngcuka, UN Women's under-secretary-general and executive director, said: "We are thrilled and honoured to work with Emma, whom we believe embodies the values of UN Women.

"The engagement of young people is critical for the advancement of gender equality in the 21st century, and I am convinced that Emma's intellect and passion will enable UN Women's messages to reach the hearts and minds of young people globally."